The present invention relates to self-regulated fertilizing irrigation systems and more specifically to systems of the kind described in prior Italian patent no. 1,061,205, which comprise a source of pressurized liquid, a duct made of flexible material, a plurality of spaced dispensers, and a regulator valve which is interposed between the source and the first dispenser of the duct.
Such systems are filled periodically, and after each filling the regulator valve, by comparing the delivery pressure with the pressure in the last portion of the duct, cuts off the delivery of the source, connecting the first portion of the duct to the discharge. Because of the consequent pressure decrease in said first duct portion, each one of the subsequent portions discharges in succession the accumulated volume of liquid through the dispenser which is arranged upstream of it with respect to the source. For this purpose, each dispenser is provided with a differential membrane valve which during filling cuts off the discharge port of the dispenser, allowing the liquid to pass from one duct portion to the other, and during discharge cuts off the passage of the liquid between the adjacent duct portions, simultaneously uncovering the discharge port of the dispenser interposed between them.
Each dispenser discharges, during each cycle, an amount of liquid (the so-called "trickle") which corresponds to the volume stored in the respective pressurized duct portion and dispenses said amount with a pressure which decreases rapidly starting from the maximum supply pressure.
Accordingly, in conventional systems, which are generally supplied at low pressure, the dispensers are directed exclusively towards the ground in order to concentrate irrigation at the base of the crops, since they are unable to effectively dispense a jet of water directed towards the head of said crops, owing to the sharp degradation of the pressure.
This is a drawback and a shortcoming of conventional systems of the specified type, which cannot be used for leaf treatments, irrigation or fertilizing irrigation, or for conventional frost protection treatments which cover the buds with a shield of ice obtained by spraying with nebulized water jets.